What Is Mold Testing? How Is Mold Testing Performed?

Broadly speaking, most mold testing involves taking a sample of
either the air or a surface. Essentially, a mold inspector "tests" the
air or surface to find out what kind of mold exists and/or if the mold found is
able to grow in the area tested.

Mold Testing: Air Samples

Air samples can be taken and analyzed in a variety of ways. The most common
method uses a "spore trap" and is called a "spore trap sample."
Spore traps work by having a known volume of air pass impact a sticky surface as it
passes through the spore trap sampling device. Most of the particles in the air
also impact this sticky surface and consequently adhere to, and are captured on,
this sticky surface. Mold spores comprise a subset of these 'particles in the air'
and also are captured on the sticky medium inside the spore trap. When the spore
trap is sent to the mold testing laboratory for analysis, the mold laboratory opens
the spore trap, applies some stains to the sticky surface that the mold spores can
absorb, and then identifies and quantifies the types of mold spores captured during
the sampling process. There are other methods of mold sampling, including culturing
or growing the mold spores captured from the air, but these are less commonly used.

Mold Testing: Surface Samples

Surface samples can be taken in a variety of ways. The three most common methods are:

Bulk samples. A piece of the sampled area is physically removed and sent
to the mold testing laboratory,

Swab samples. Something akin to a cotton swab is rubbed across the area
being sampled, often a measured area, and subsequently sent to the mold testing laboratory, and

Tape samples. A piece of clear tape is pressed against and removed from
the area being sampled, presumably picking up and removing part of any mold that
was present on the surface, and then set to the mold testing laboratory for analysis.

After the mold samples arrive at the
mold testing laboratory,
there are many ways to analyze these mold samples. The most common methods involve
transferring relevant sections (or all) of the submitted mold sample onto a glass
microscope slide, adding a stain that mold spores can absorb, and then evaluating
the sample for evidence of mold growth.